Microbial Succession

Microbial Community Assembly and Ecosystem Succession This project addresses hypotheses regarding the relationship between microbial community assembly, environmental parameters, and ecosystem functioning during primary succession (following glacial retreat) and secondary succession (following forest fires). High-throughput community analyses and metagenomics are employed to explore the factors controlling how microbial communities develop (microbial assembly processes) and the relative roles of environmental (niche) and random (neutral) controls in structuring microbial communities (Nemergut et al. 2013). A wide array of biogeochemical processes are monitored along the chronosequences in order to link community assembly with ecosystem functions. Research sites are in Colorado, Alaska and Perú. Recent publications from this work highlight the unexpected importance of nutrient limitations (especially phosphorus limitation) in controlling both community assembly and ecosystem functions during the microbial stages of ecological succession in both Perú (Knelman et al. 2014, Schmidt et al. 2012) and Alaska (Darcy & Schmidt 2016, Schmidt et al. 2016). One of the driving force behind this project was Professor Diana Nemergut, who passed away on December 31st, 2015. Funding was provided by NSF grants DEB-0922267 (Links between Soil Biogeochemistry and Microbial Community Dynamics Along Recently Deglaciated Chronosequences), and DEB-1258160 (“Collaborative Research: Relative Controls of Niche vs. Neutral Microbial Community Assembly Processes Over Ecosystem Function Post-Disturbance").

​Heat maps showing the landscape patterns of total organic carbon (TOC) and Total organic nitrogen (TON) across the MF Toklat Glacier chronosequence, Denali National Park. Notethe hotspots of TOC near the glacier terminus (C)and at the farthest distance from the glacier terminus (D).In contrast TON hotspots were more randomly arrayedalong the chronosequence. This is Figure 7 from this paper: Ecosystems 19: 1164–1177 (2016). [Reprint]

This figure was created by Andrew King, by overlaying landscape patterns in the parameters onto an aerial photo of the field site